Stress, Memory, and Hormonal Influence: Considering Ovarian Hormones in Emotional Memory Intrusions

Women’s greater vulnerability to intrusive memories following trauma may be partially explained by the influence of ovarian hormones on memory consolidation processes. Contributing to accumulating research examining the influence of ovarian hormones on the development of intrusive memories, we hypothesized that cyclical fluctuations in estradiol and progesterone, not merely absolute levels, contribute to this risk. We further hypothesized that hormonal contraceptives, which effectively eliminate fluctuations and keep ovarian hormones at chronic low levels, can convey protective effects against memory intrusions following analogue trauma exposure. We examined the development of memory intrusions following trauma film stressor exposure among men (n = 27), hormonal contraceptive (HC) users (n = 41), and naturally cycling (NC) women in the early follicular (EF; n = 24), late follicular (n = 20), ovulatory window (n = 14), and luteal phases (n = 21) for 5 days to assess whether low ovarian hormone levels convey a protective effect for women. Contrary to hypotheses, this study found no support for this prospect; rather, exposure to stressors during the window around ovulation increased the risk for more frequent intrusive memories. Enhanced stress responsivity may have particular effects on ovulation, promoting evolutionary fitness.